As described in PLT 1 and PLT 2 below, there has been known a starting apparatus in which the inner ring portion and the output axle of a one-way clutch are coupled with each other through helical spline coupling. In the technology disclosed in PLT 1, in order to receive axial-direction anti-motor-side thrust force that acts on the output axle through helical spline coupling, a stopper 16 is provided at the axial-direction anti-motor side of an outer helical spline provided in the inner circumferential surface of an inner ring portion.
In the technology disclosed in PLT 2, in order to receive axial-direction anti-motor-side thrust force that acts on the output axle through helical spline coupling, a ring-shaped member is fit to the axial-direction motor-side end portion of an inner helical spline provided on the outer circumferential surface of the output axle.